Hybrid scanner fabricator

ABSTRACT

A system and method to fabricate three dimensional objects. A set of fabrication tools include at least a coarse deposition head and a fine additive head, a fine subtractive head or both employed concurrently within a single housing. A scanner may also be used within the housing to perform interleaved scanning of the partial fabrication during the fabrication. The process may be adjusted based on the scan results.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/781,312 filed May 17, 2010 entitled “HYBRID SCANNER FABRICATOR.”

FIELD

The invention relates to a method and apparatus for fabricating threedimensional objects. More specifically, embodiments of the inventionrelate to a hybrid applicator having coarse and fine fabricationcapabilities and, in some cases, interleaved scanning.

BACKGROUND

Various three dimensional printers exist which can be used to fabricatea three dimensional object from a digital model. Typically, suchprinters spray down a series of fine dots of a plastic materialperpendicularly to a build surface. The dot size is selected to permitcreation of the minimum feature size desired. As a result, when largerthan the minimum feature size is desired, many more dots must beaccumulated to create the feature. Additionally, a sacrificial materialmust be used to support any features that are not perpendicularlysupported by the build surface. As a result, the build process tends tobe quite slow.

Other existing three dimensional fabrication systems employ a gel, whichis extruded and cured to form a three dimensional object. However, thissystem has many of issues described above and additionally suffers fromsagging and deformation during cure.

Additionally, anomalies or inconsistencies within the build processcannot be identified, while the process is occurring. Thus, it is onlyafter the time is consumed for the complete fabrication that thefinished product may reveal the build was unsuccessful. Thus, an entireadditional build process must be undertaken to create a new object. Amore reliable and faster apparatus and system for forming threedimensional objects from a digital representation is desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the invention are illustrated by way of example andnot by way of limitation in the figures of the accompanying drawings inwhich like references indicate similar elements. It should be noted thatreferences to “an” embodiment of the invention in this disclosure arenot necessarily to the same embodiment, and they mean at least one.

FIG. 1 is a schematic diagram of a system of one embodiment of theinvention.

FIG. 2 is a schematic diagram of a control subsystem for one embodimentof the invention.

FIG. 3 is a flow diagram of operation according to one embodiment of theinvention.

FIG. 4 is a schematic diagram showing oriented deposition according toone embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of a system of one embodiment of theinvention. Within the housing 100, a plurality of fabrication tools 108is disposed. Fabrication tools 108 may be disposed as a single head orindividual independently moveable heads. In one embodiment, a coarseprint nozzle 102 is provided to deposit a fabrication material within awork space 110 at a granularity of greater than 0.030 inches perdeposition. As used herein, granularity greater than x means that eachdeposition occupies an area greater than x. A work surface (alsoreferred to as a build surface) 112 provides a support for thefabrication of a three dimensional target object 114. In one embodiment,a plurality of servos move the work surface 112 relative to thefabrication tools 108 in x, y, z and rotational directions responsive tocomputer control.

In some embodiments, because the coarse nozzle 102 may deposit volumesof material that will not cool quickly enough under ambient conditions,an active cooling arm 120 may be used to provide active localizedcooling to material deposit by coarse nozzle 102. In some embodiments,coarse nozzle 102 may also be oriented to a different angularorientations 122 relative to the work surface 112. This is discussed inmore detail with reference to FIG. 4 below. In some embodiments thecross section of the nozzle 102 may also be changed so that a singledeposition may have a different shape than a subsequent or priordeposition.

In some embodiments, also included within the fabrication tools 108 is afine nozzle 104 to deposit smaller amounts of material than the coarsenozzle. This permits detailing of an object created by the coarse nozzle102 so that large features can be rapidly built with the coarse nozzle102 and small features added with the fine nozzle 104. In oneembodiment, fine nozzle 104 deposits material with granularity less than0.015 inches per deposition. As used herein, a granularity of less thanx means a deposited spot occupies an area less than x. Also includedwithin the fabrication tools 108, in one embodiment of the invention, isa subtractive head 106, which can subtractively detail the object 114.In one embodiment, subtractive head 106 is a computer controlled millingbit. In some embodiments, performing the subtractive detailing beforeaddition of a subsequent layer, access to detail desired features can beassured.

In one embodiment of the invention, a three dimensional scanner 130 isprovided within the housing 100 to scan the object 114 duringfabrication. This permits the fabrication process to be adjustedresponsive to identification of variance in the fabricated object 114from the intended object as reflected in the digital model sourcing thedata for the fabrication. In some embodiments, a scanner 130 may uselaser ranging to create the three dimensional model of the work inprocess 114. Other scanning methods are also within the scope andcontemplation of the invention.

In some embodiments, the intermediate scanned model may be analyzed todetermine whether corrective measures may be deferred until later in thefabrication process where such deferral would improve the efficiency ofthe fabrication. For example, if detailing with fine nozzle 104 may bedeferred because it will still be possible to create that detail at alater point, then the analysis from the intermediate scan may cause thedeferral of that detailing. However, where that aspect may or will nolonger be accessible after further fabrication steps, the correctiveaction or detailing action must be taken before such subsequentfabrication actions obscure the area to be detailed.

In some embodiments, such as shown in FIG. 1, the fabrication tools 108and scanner 130 remain fixed and the work surface 112 is moved to effectthe relative motion between the point object and the tool 108 andscanner 130. In other embodiments, the tools 108 and scanning 130 movemore while the target object remains fixed. Additionally, while andembodiment with a coarse nozzle and a fine nozzle is described andshown, a system employing a range of multiple nozzles is within thecontemplation of the invention.

FIG. 2 is a schematic diagram of a control subsystem for one embodimentof the invention. A controller 200 interacts with a plurality of drivers208, a three dimensional scan head 204, and monitoring software 202.Controller 200 uses a digital model of an object to be fabricated toinstruct the drivers 208.

During fabrication controller 200 may periodically initiate a scan ofthe partial object using scan head 204. The resulting scan data may beprovided to the monitoring software module 202, which may conduct ananalysis. For example, monitoring software module 202 may performcomparison of existing source model relative to what has been built inthe partial object. The comparison may reflect a need to modify one ormore aspects of the build, or do additional additive or subtractivedetailing. An evaluation may also be undertaken to determine whethersuch additional detailing may be deferred. The deferral of the detailingshould be undertaken where such deferral makes the overall fabricationmore efficient. For example, where deferral of detailing reduces thenumber of movements the object must undergo in the process. Deferralshould generally not be undertaken when there is no efficiency gain orwhere it may or will not be possible to perform detailing at a laterpoint during the process. Drivers 208 include servo drivers to drivenotions 210, 212, 214, and 216 to drive the relative motion between thework surface (112 in FIG. 1) and the fabrication tools (108 in FIG. 1).As shown, motor 210 controls x motor, motor 212 controls y motion, motor214 controls z motor and motor 216 controls rotation. An additionaldriver drives motor 218, which controls the orientation and crosssection of the coarse nozzle. Additionally drivers 208 to includedrivers to drive fine head deposition 220 coarse deposition 222 and themill motor 224.

FIG. 3 is a flow diagram of operation according to one embodiment of theinvention. At block 302, the coarse nozzle is oriented for desiredangular deposition relative to the underlying material. In some cases,the model nozzle may deposit perpendicularly achieving a flat depositionzone 302 as shown in FIG. 4. In other cases, the nozzle may be orientedto deposit an angle θ relative to the perpendicular to achieve anangular deposition zone 404 in FIG. 4.

At block 304, the system drives the coarse nozzle to deposit material inthe orientation selected at block 302. At decision block 306, adetermination is made whether a scan should be interleaved at this pointin the fabrication process. If a scan should be interleaved the objectis scanned at block 308 and the three dimensional model of the partialobject is created. At block 310, the scan of the partial object isanalyzed relative to, for example, the model on which the fabrication isbased to evaluate if changes should be made to the fabrication processconcurrently.

For example, variations between the intended design reflected in thesource model and what has actually been created may necessitateadditional detailing or changes in the calibration of the system.Additionally, determinations can be made whether detailing can bedeferred to the extent that such deferral will improve the efficiency ofthe fabrication process by, for example, reducing the number of therelative movement of the fabrication heads and the object.

A determination is made at decision block 312 whether detailing isrequired. If detailing is required at decision block 314, adetermination is made whether to what extent the detailing can bedeferred. If the detailing is required and cannot be deferred, theobject detailed with the fine resolution additive or subtractive head atblock 316. If no detailing is required or after the detailing iscomplete at block 316, the decision is made at decision block 318 wherethe fabrication is complete. If the fabrication is not complete, thesystem returns for further deposition. Otherwise the process ends.

While embodiments of the invention are discussed above in the context offlow diagrams reflecting a particular linear order, this is forconvenience only. In some cases, various operations may be performed ina different order than shown or various operations may occur inparallel. It should also be recognized that some operations describedwith respect to one embodiment may be advantageously incorporated intoanother embodiment. Such incorporation is expressly contemplated.

It should be appreciated that reference throughout this specification to“one embodiment” or “an embodiment” means that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention.Therefore, it is emphasized and should be appreciated that two or morereferences to “an embodiment” or “one embodiment” or “an alternativeembodiment” in various portions of this specification are notnecessarily all referring to the same embodiment. Furthermore, theparticular features, structures or characteristics may be combined assuitable in one or more embodiments of the invention.

In the foregoing specification, the invention has been described withreference to the specific embodiments thereof. It will, however, beevident that various modifications and changes can be made theretowithout departing from the broader spirit and scope of the invention asset forth in the appended claims. The specification and drawings are,accordingly, to be regarded in an illustrative rather than a restrictivesense.

What is claimed is:
 1. A hybrid system having both a three dimensionalprinter and a three dimensional scanner comprising: a structure defininga work area; an interface to receive digital data defining a geometryfor a three-dimensional object to be fabricated; a nozzle coupled to thestructure to deposit material to fabricate a three dimensional objectwithin the work area; a scan head coupled to the structure concurrentlywith the nozzle to capture three dimensional information about a targetobject within the work area, wherein the system creates a threedimensional digital model of the target object based on the threedimensional information captured by the scan head; and a drive systemsharing in common at least one axis of motion to cause movement betweenboth the nozzle and the scan head, relative to the three dimensionalobject.
 2. The hybrid system of claim 1 further comprising: a controlsubsystem that monitors scan head data and controls the nozzle to adjustthe fabrication process to improve at least one of the speed or accuracyof the fabrication of the three dimensional object.
 3. The hybrid systemof claim 1 wherein the scanner periodically images the three dimensionalobject during fabrication further comprising: a monitoring module toadjust the scanning and printing activity to improve fabricationefficiency.
 4. The hybrid system of claim 1 further comprising: a shapeadjustment subsystem coupled to the nozzle to change at least one of theorientation or cross-sectional shape or size of the material depositedin the build zone.